Currently, display technology mainly comprises liquid crystal display (LCD), organic light-emitting diode display (OLED), plasma display (Plasma Display Panel, PDP) and electronic ink display and etc. Among them, OLED device with its thin, active light, fast response speed, wide viewing angle, rich colors and high brightness, low power consumption, resistance to high and low temperatures and many other advantages is recognized in the industry as the third generation of display technology after the LCD display, and is widely used in smart phones, tablet PCs, television and other end products.